IBM advances bring quantum computing closer to reality

Scientists figure out how to detect errors in quantum calculations

IBM scientists say they have made two critical advances in an industrywide effort to build a practical quantum computer, shaving years off the time expected to have a working system.

"This is critical," said Jay Gambetta, IBM's manager of theory of quantum computing. "The field has got a lot more competitive. You could say the [quantum computing] race is just starting to begin… This is a small step on the journey but it's an important one."

Gambetta told Computerworld that IBM's scientists have created a square quantum bit circuit design, which could be scaled to much larger dimensions. This new two-dimensional design also helped the researchers figure out a way to detect and measure errors.

Quantum computing is a fragile process and can be easily thrown off by vibrations, light and temperature variations. Computer scientists doubt they'll ever get the error rate down to that in a classical computer.

Because of the complexity and sensitivity of quantum computing, scientists need to be able to detect errors, figure out where and why they're happening and prevent them from recurring.

IBM says its advancement takes the first step in that process.

"It tells us what errors are happening," Gambetta said. "As you make the square [circuit design] bigger, you'll get more information so you can see where the error was and you can correct for it. We're showing now that we have the ability to detect, and we're working toward the next step, which would allow you to see where and why the problem is happening so you can stop it from happening."

Quantum computing is widely thought to be the next great step in the field of computing, potentially surpassing classical supercomputers in large-scale, complex calculations.

Quantum computing would be used to cull big data, searching for patterns. It's hoped that these computers will take on questions that would lead to finding cures for cancer or discovering distant planets – jobs that might take today's supercomputers hundreds of years to calculate.

IBM's announcement is significant in the worlds of both computing and physics, where quantum theory first found a foothold.

Quantum computing, still a rather mysterious technology, combines both computing and quantum mechanics, which is one of the most complex, and baffling, areas of physics. This branch of physics evolved out of an effort to explain things that traditional physics is unable to.

With quantum mechanics, something can be in two states at the same time. It can be simultaneously positive and negative, which isn't possible in the world as we commonly know it.

For instance, each bit, also known as a qubit, in a quantum machine can be a one and a zero at the same time. When a qubit is built, it can't be predicted whether it will be a one or a zero. A qubit has the possibility of being positive in one calculation and negative in another. Each qubit changes based on its interaction with other qubits.

Because of all of these possibilities, quantum computers don't work like classical computers, which are linear in their calculations. A classical computer performs one step and then another. A quantum machine can calculate all of the possibilities at one time, dramatically speeding up the calculation.

However, that speed will be irrelevant if users can't be sure that the calculations are accurate.

That's where IBM's advances come into play.

"This is absolutely key," said Jim Tully, an analyst with Gartner. "You do the computation but then you need to read the results and know they're accurate. If you can't do that, it's kind of meaningless. Without being able to detect errors, they have no way of knowing if the calculations have any validity."

If scientists can first detect and then correct these errors, it's a major step in the right direction to building a working quantum computing system capable of doing enormous calculations.

"Quantum computing is a hard concept for most to understand, but it holds great promise," said Dan Olds, an analyst with The Gabriel Consulting Group. "If we can tame it, it can compute certain problems orders of magnitude more quickly than existing computers. The more organizations that are working on unlocking the potential of quantum computing, the better. It means that we'll see something real that much sooner."

However, there's still debate over whether a quantum computer already exists.

A year ago, D-Wave Systems Inc. announced that it had built a quantum system, and that NASA, Google and Lockheed Martin had been testing them.

Many in the computer and physics communities doubt that D-Wave has built a real quantum computer. Vern Brownell, CEO of the company, avows that they have.

"I think that quantum computing shows promise, but it's going to be quite a while before we see systems for sale," said Olds.

IBM's Gambetta declined to speculate on whether D-Wave has built a quantum computing but said the industry is still years away from building a viable quantum system.

"Quantum computing could be potentially transformative, enabling us to solve problems that are impossible or impractical to solve today," said Arvind Krishna, senior vice president and director of IBM Research, in a statement.

IBM's research was published in Wednesday's issue of the journal Nature Communications.

IBM Research

This story, "IBM advances bring quantum computing closer to reality" was originally published by
Computerworld.